"In our contacts with partners in NATO and in the region, we are calling on them not to seek pretexts for carrying out a military scenario or to introduce initiatives such as humanitarian corridors or buffer zones," Gatilov said, according to the Interfax news agency.

Russia and China have vetoed three UN Security Council resolutions condemning Syrian President Bashar Assad and blocked attempts to impose sanctions on the country or intervene more directly in its conflict.

Syria's neighbor Turkey has floated the idea of setting up "safe zones" inside Syria to protect civilians but that would also have to be approved by the Security Council.

Gatilov urged restraint between Syria and NATO-member Turkey, one of Assad's harshest critics. Ankara has repeatedly complained of artillery and gunfire spilling over its border and last week it signaled it would take action if there was a repeat of a mortar strike on its territory from inside Syria.

"We believe both Syrian and Turkish authorities should exercise maximum restraint in this situation, taking into account the risings number of radicals among the Syrian opposition who can intentionally provoke conflicts on the border," Gatilov was quoted as saying.

Assad gives orders to 'cleanse' Aleppo

Meanwhile, Syrian President Bashar Assad visited the city of Aleppo to take a first-hand look at the fighting between government forces and rebels, a Lebanese paper said on Tuesday. The report also claimed that Assad has ordered 30,000 more troops into the battle.

Al-Diyar newspaper, which is known for its pro-Assad stance, said the president had flown by helicopter at dawn from the presidential palace in Damascus to Aleppo. It did not specify what day the trip started but said that Assad was still in Aleppo. The visit was decided on after reports that the situation in the city, Syria's largest and its commercial center, had become very serious.

"President Assad ordered units 5 and 6, estimated to be 30,000 soldiers and 2,000 personnel carriers, to move from Hama to Aleppo and to attack any occupied areas of Aleppo province from the Turkish border," it said. The paper said that Assad gave orders that Aleppo must be "cleansed" during the visit.

Reuters was unable to independently verify the report.

Rebels mounted a new offensive last week to seize the city, which was until July firmly under Assad's control. They claim to hold most of the Old City but are struggling to hang on to their positions in the face of heavy artillery fire.

The rebel forces are in the east and Assad's forces in the west of Aleppo. Fires started by the combat have gutted the historic market in the Old City, a world heritage site.

Opposition activists say 30,000 people have been killed in the 18-month-old anti-Assad uprising, which has grown into a full-scale civil war.